This invention relates to a load handling apparatus comprising a frame, an apparatus head mounted on the frame and rotatable in a horizontal plane, and an arm mounted on the apparatus head. The arm has an inner portion which is in the form of a parallelogram linkage with two parallel longitudinal links which are swingable in a vertical plane relative to the apparatus head and are connected by joints, at their ends, to an outer transverse link and an inner transverse link parallel thereto. The arm also has an outer portion which includes an extension of the outer transverse link of the inner portion and supports, at its outer extremity, a holder for a load.
With prior art apparatuses of this type it has not been possible to carry out, in a simple manner, an accurate horizontal translation of the load. Furthermore, the prior art apparatuses utilise drives actuating the arm for raising and lowering of the load. These drives usually include chains or the like, and, because of this, do not permit a gentle start and stop of the movement of the load. Finally, the prior art apparatuses utilise springs for balancing the arm, but these springs often provide poor balancing. With heavy loads, moreover, dangerous return forces arise in the extreme positions of the arm. It is also necessary to employ counterweights located outside the apparatus head which impedes the movement of the apparatus.